how to define an integral function

I want to define a function in the integral form

f(x)=integral(g(z), z=0, z=x)

as an example:

for which I wrote:

fun = @(z) z^2+3*z-1;
x=linspace(0,1,100);
y = integral(fun,0,@(x) x)
plot(x,y)

But Matlab returned the following error:

Error using integral (line 85)
A and B must be floating-point scalars.

Error in IntegralFunction (line 8)
y = integral(fun,0,@(x) x)

Is it possible at all to do this in Matlab?

Answer 1

[Torsten]

fun=@(z)z.^2+3*z-1;
F=@(x)integral(fun,0,x);
F(10)

[Saeid]

Danke, Torsten!

[Saeid]

Hi again Torsten! Actually, my aim to define a function like this was for the final result (in this case F(x)=x^3/3+3*x^2/2-x) to be a coefficient in a differential equation. Something like: y"+F(x).y'=y"+(x^3/3+3*x^2/2-x)*y'=0 Do you know if that is possible in Matlab?

[Torsten]

Yes, it's possible just the way I showed you above. What exactly is the problem when you want to use it in your context ?

[Saeid]

I tried the following format but it didn't work:

tspan = [0 5];
y0 = 0;
[t,y] = ode45(@(t,y) DYDT(t,y) , tspan, y0);
plot(t,y,'-o')

function dydt=DYDT(t,y)
    fun=@(z)z.^2+3*z-1;
    dydt=@(y)integral(fun,0,y)
end

[Aishwarya Kasarla]

Hey, I am also stuck with the same proble, did you find the solution? Can you please help me out with this?